Spider builds life-sized replicas of itself to escape predators

A species of spider has proved the ultimate escape artist by building full-sized decoys of itself to distract predators.
It could help explain why many arachnids decorate their nests with bizarre ornaments such as prey remains, despite this making their webs more obvious to hunters.

The Cyclosa mulmeinensis spider uses a novel anti-predator device. It builds an exact replica of itself as a decoy to wasps

Animals often use camouflage to try and disguise themselves from predators. Stick insects look like twigs and chameleons change their skin colour to suit their surroundings.
Others opt for anti-predator devices. Squid protect themselves from enemies by shooting out ink with a mucas membrane around it to retain the shape and size of itself as it swims away.
The Cyclosa mulmeinensis spider, however, is the first example of a creature that builds an exact replica model of itself as a decoy.

A female Cyclosa mulmeinensis spider (bottom right) is seen with two egg shapes sacs that act as decoys

Biologists Ling Tseng and I-Min Tso from Tunghai University in Taiwan studied the spider species on Orchid Island, off the coast of Taiwan.
They noticed it decorated its web with pellets and egg sacs that were the same size as its own body.
The researchers also found that these decorations appeared to wasps to be the same colour, and reflect light in the same way, as the spiderís body.
In short, the spider made decorations that were of the same size, shape and appearance as itself.
'Our results show that this vulnerable spider protects itself from predator attacks by constructing decoys that increase the conspicuousness of the web, and resemble its own appearance in size and colour,' the researchers told BBC Earth News.
They found the survival technique was affective with wasps attacking the decoys rather than the spider.

'When both spiders and web decorations are present on the same web, they look like a string of nearly identical oval objects to the predators,' said Tso.
'The benefit of successful escape from predator attack seems to outweigh the cost of increased detection.'